This invention relates to a device for the controlled dispensing of pellets and, in particular, to a dispenser for a pelletized rodenticide.
The ever-increasing awareness of the effects of toxic substances, both on individuals and on the surrounding environment, have created a demand for products using toxic materials in a controlled and confined manner. In the past, toxic substances in granular or pelletized form were scattered on the ground or placed on open containers to provide a measure of control of rats, mice and other vermin. The practice of scattering toxic substances is no longer acceptable and the use of open containers wherein the toxic substances might be available to small animals and children are in disfavor. Furthermore, the use of toxic substances in urban and suburban areas wherein the population density is relatively large is a matter of great concern.
The desire to control distribution of toxic substances has led to poison bait stations such as shown in U.S. Pat. No. 2,977,711 wherein a bait dish is provided with a separate cover containing apertures sized to exclude small animals. The use of a feeding dish requires that the users transfer the toxic substance from a larger container to the feeding dish thereby exposing both themselves and the environment to the substance. In addition, the placement of the cover is a temporary matter for the cover can be dislodged exposing the open dish to other animals. A combination dish and cover structure is shown in U.S. Pat. No. 2,710,485 wherein the cover is attached to the base structure. Apertures define passageways and control access with the toxic material being made available through inner openings. While the dispenser is still loaded by the user, the problem of dislodging the cover is eliminated. However, the handling and movement of this device creates an opportunity for spillage since the toxic substance is not fully confined during movement. A preloaded and sealed dispensing device is shown in U.S. Pat. No. 4,211,028 wherein the poison is contained in a chamber having a wall made of a consumable substance having a taste or odor attractive to rodents. The problems associated with the transfer of toxic substances to the device and the possibility of spillage occurring during initial placement of the device are eliminated by this particular structure. However, once the rodent has chewed through the containing wall, the poison tumbles out and is available to the rodent and to other animals. Furthermore, the poison bait is exposed to moisture in this type of device and to the marking activities of rodents which serve to discourage use by other rodents.
A different approach is taken in the dispensing apparatus shown in U.S. Pat. No. 4,746,033 wherein a vertical pipe serves as a reservoir for granular or pelletized toxic material. The device is augured into the ground with a container proximate to the bottom of the tube contacting the ground to serve as a catchment for contained material. A protective cover is slidably mounted on the tube and extends outwardly of the containers so that access can be denied to larger animals and it can be covered during nonoperating periods. The tube communicates with the lower container through one or more apertures and the granular material flows downwardly and outwardly into the container. The device is not preloaded so that the user must fill the tube from a larger storage container. The device is intended to be used in agricultural fields which enables it to be inserted into the ground.
Accordingly, the present invention is directed to the provision of an improved device for the controlled dispensing of toxic substances wherein the device can be preloaded by the addition of pellets to an inverted cap followed by the urging of the base into engagement with the cap. In addition, the device is constructed to enable it to be readily opened by the user to a defined open position without spillage of the contents. The defined opening exposes the toxic bait about the peripheral region of the device to provide a 360.degree. access to the bait. In addition, the present invention limits the availability of the toxic substance to feeding vermin by controlled dispensing about the peripheral region thereby reducing the likelihood of materials flowing outwardly of the device. Thus, the user need not handle the toxic substance and the opportunity for unintentionally scattering the material on the ground, either during use of during movement to another site, is essentially eliminated.
The subject invention is formed of two parts each of which is well suited for injection molding to provide a low cost of manufacture. The parts are provided with a guide and mating guideway for relative rotation and vertical movement. Also, an internal stop is provided to define the full open position of the dispenser. The relative movement between the two parts controls the amount of material available as well as establishing the size of the opening through which the vermin may feed. The opening extends around the device to provide access to the bait therein. An alignment rib is provided in the device to facilitate assembly and to direct the placement of the guide in the guideway for the subsequent opening of the dispenser prepatory to use thereof.